I cannot speak to your 16-gallon tank, but my 67 Barracuda has an 18-gallon tank, and some things may be similar. The pickup point (with the suction filter) is “towards” the bottom of the tank, and the float the goes down to about the same level. That’s fine, but most people do not know that there is about 3.5 gallons below that point.
The float is at its lowest level and the pickup tube is just above the level of the gas. So, you’re out of gas, but you have 3.5 gallons left. I know this for a fact. I tested it.